package tools

import (
	"bytes"
	"encoding/gob"
	"io"
	"io/ioutil"
	"os"
	"path/filepath"
)

func DeepCopy(dst, src interface{}) error {
	var buf bytes.Buffer
	if err := gob.NewEncoder(&buf).Encode(src); err != nil {
		return err
	}
	return gob.NewDecoder(bytes.NewBuffer(buf.Bytes())).Decode(dst)
}

// Copy copies src to dest, doesn't matter if src is a directory or a file
func Copy(src, dest string) error {
	src = ExpandHomeDir(filepath.Clean(src))
	dest = ExpandHomeDir(filepath.Clean(dest))

	info, err := os.Stat(src)
	if err != nil {
		return err
	}
	return copy(src, dest, info)
}

// "info" must be given here, NOT nil.
func copy(src, dest string, info os.FileInfo) error {
	if info.IsDir() {
		return dcopy(src, dest, info)
	}
	return fcopy(src, dest, info)
}

func fcopy(src, dest string, info os.FileInfo) error {
	f, err := os.Create(dest)
	if err != nil {
		return err
	}
	defer f.Close()

	if err = os.Chmod(f.Name(), info.Mode()); err != nil {
		return err
	}

	s, err := os.Open(src)
	if err != nil {
		return err
	}
	defer s.Close()

	_, err = io.Copy(f, s)
	return err
}

func dcopy(src, dest string, info os.FileInfo) error {
	if err := os.MkdirAll(dest, info.Mode()); err != nil {
		return err
	}

	infos, err := ioutil.ReadDir(src)
	if err != nil {
		return err
	}

	for _, info := range infos {
		if err := copy(
			filepath.Join(src, info.Name()),
			filepath.Join(dest, info.Name()),
			info,
		); err != nil {
			return err
		}
	}

	return nil
}